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Positive factors

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Source: — Data Sufficiency |

by SoCan » Sun May 29, 2011 10:38 am
Akansha wrote:If integer n is > 1, is n = 2?
a. n has exactly 2 positive factors
b. The difference of any 2 distinct positive factors of n is odd


OA is B
1) n can be any prime number, by definition
2) n cannot be an odd number, because every odd number has 1 and itself as a factor, and the difference between these is always even. Except for 2, every even number has 2 and itself as a factor, and that difference is always even. Two only has two factors, 2 and 1, and that difference is odd.

B is sufficient.
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